GPT-4o nano requires a Tier 2 OpenAI API key to work in Clay. Check your OpenAI usage tier at platform.openai.com/settings/organization/limits.
If you're on Tier 1 or free plan, you'll need to upgrade to Tier 2. Contact OpenAI support and ensure you have the minimum required balance in your OpenAI account to expedite the upgrade process.
You can also verify your API key is correct at platform.openai.com/account/api-keys and update it in Clay if needed.